Bently Nevada 990-04-50-03-01 Vibration Transmitter

Bently Nevada 990-04-50-03-01 Vibration Transmitter

Product Introduction

The Bently Nevada 990-04-50-03-01 belongs to the 990 series of vibration transmitters. It accepts input from one non-contacting 3300 NSv proximity probe and an extension cable. This device then converts radial vibration into a standard 4-20 mA signal.

Many industrial plants choose this 990-04-50-03-01 for reliable shaft vibration monitoring. The full-scale option is set to 0-4 mils pp (0-100 μm pp). Furthermore, the system length reaches 5.0 meters (16.4 feet), which simplifies installation in tight panels.

Technical Specifications

Power and Output
The transmitter requires +12 to +35 Vdc at its terminal. It operates in a two-wire configuration. Maximum loop resistance equals 1,000 Ω including cable at 35 Vdc. Typical current limiting sits at 23 mA.

4-20 mA Loop Accuracy
Accuracy stays within ±1.5% over the specified full-scale range. Bently Nevada rates this accuracy from the TEST signal input to the voltage measured across a 250 Ω loop resistance. Note that the ±1.5% error adds to the Prox Out Incremental Scale Factor.

Frequency Response
The frequency response ranges from 5 Hz to 6,000 Hz (+0, -3 dB). This wide bandwidth captures most common vibration frequencies in rotating machinery.

Probe Gap Requirement
You must gap the probe between 0.5 and 1.75 mm (20 and 55 mils) from the target. This ensures the full-scale range performs correctly.

Not OK / Signal Defeat
When a Not OK condition occurs, the output drops below 3.6 mA within 100 µs. After the Not OK condition clears, the signal restores within 2-3 seconds.

Environmental and Mechanical Limits

Transmitter Temperature

• Operating temperature: -35°C to +85°C (-31°F to +185°F)

• Storage temperature: -51°C to +100°C (-60°F to +212°F)

Mounting and Weight
The unit mounts on a standard DIN rail using option 03 DIN clips and screws. Total weight is 0.43 kg (0.9 lbm).

Hazardous Area Approval
This model carries agency approval option 01 CSA Division 2. It suits nonhazardous, Zone 2, or Division 2 hazardous area locations. The power supply should be 28 V.

Frequently Asked Questions (FAQ)

1. Can I use this transmitter with a 3300 XL probe instead of the NSv?
The Bently Nevada 990 series specifically accepts the 3300 NSv proximity probe. Using other probes may affect accuracy and frequency response.

2. What happens if the probe gap falls outside the 0.5-1.75 mm range?
The output may not cover the full 0-4 mils pp range. Additionally, linearity could degrade. Always verify the gap before commissioning.

3. How long does it take for the output to recover after a Not OK condition?
Recovery time equals 2-3 seconds after the Not OK condition is removed. During this period, the output stays below 3.6 mA.

4. Is this transmitter suitable for thrust measurement?
No. The 990-04-50-03-01 is designed for radial vibration monitoring. For thrust applications, consider the Bently Nevada 991 series instead.

5. Can I extend the cable beyond 3 meters from the Proximitor output?
No. The maximum leadwire length for the Proximitor Sensor Output with BNC connector is 3 meters (10 feet). Exceeding this limit may degrade signal quality.